Analysis of Multicell Box Gates for Dry Docks

Analysis is made of a cellular steel gate structure, consisting of a series of horizontal webs, vertical webs, and skin plating on both sides. The usual structural design is based on considering the gate as a rectangular slab supported on three sides. An alternative and more realistic method of analysis is presented. The structure is considered as composed of an assembly of plane cover and web elements. The lines of intersections of these elements intersect at finite number of points, at which conditions of equilibrium, compatibility of deformations and boundary conditions are satisfied. The comparison between this method and the idealized plate method shows that the plate method can furnish sufficiently good information regarding the distribution of the normal stresses in the cover plates. Also, except for a zone around the edges, the plate method furnishes sufficiently good information regarding the distribution of the shear stresses in the cover plates. However, the plate method fails to furnish sufficiently good information regarding the distribution of the shear stresses in the webs or the reactions at the supports.